Transtage, given the United States Air Force designation SSB-10A, was an American upper stage used on Titan III rockets, developed by Martin Marietta and Aerojet.
Manufacturer | Martin Marietta |
---|---|
Country of origin | United States |
Used on | Titan III |
General characteristics | |
Height | 4.57 meters (15.0 ft) |
Diameter | 3.05 meters (10.0 ft) |
Gross mass | 12,247 kilograms (27,000 lb) |
Engine details | |
Powered by | 2AJ10-138 |
Maximum thrust | 8,000 lbf (36 kN) each[1] |
Specific impulse | 311 seconds (3.05 km/s) |
Burn time | 440 seconds |
Propellant | Aerozine 50 / N2O4 |
Transtage was developed in anticipation of a requirement to launch military payloads to geostationary orbit; a contract for development of the stage was issued on 20 August 1962.[2] Transtage used a pressure-fed two-chamber configuration, using Aerozine 50 fuel and nitrogen tetroxideasoxidizer; the thrust chambers were gimbaled for steering and each produced 8,000 lbf (36 kN) of thrust.[3] The design specification required up to three restarts during the first six hours of a mission.[4]
Forty-seven Titan III launches are known to have used Transtage upper stages;[5] of those, three are known to have suffered launch failures.[6] The first launch, boosted by a Titan IIIA, occurred on 1 September 1964;[7] the Transtage failed to pressurize, resulting in premature engine cutoff, and a failure to reach orbit.[6] The second launch, on 10 December, was successful, and all ensuing launches used the Titan IIIC launch vehicle. The last launch of a Transtage was on 4 September 1989, boosted by a Titan 34D rocket.[6]